Device wherewith to set the points of beam compasses and the like



March 6, 1945. A, s. MCDQNNELL 2,370,741

DEVICE WHEREWITH TO SET THE POINTS OF BEAM-COMPASSES AND THE LIKE Filed April 20, 1945 5 Sheetsl-Sheet 2 m SO 27 4 25 21 f a3 32 -/\l w f ,i o i 39 u P- l l f-l l100 l 2f. wwviv E* 24 36 Q 2 March 6, 1945. A, s, MCDONNELL l 2,370,741

DEVICE WHEREWITH -TO SET THE POINTS OF BEAM-COMPASSES AND THE LIKE Filed April 20, 1943 3 Sheets-Sheet 3 EIHIIHII U W fvr/2@ Patented Mar. 6, 1945 UNITED STATE DEVICE WHEREWITH 'ros'ET THE POINTS F BEAM ooMPAssEs AND THE LIKE This invention relates to a unique and eiiicient device wherewith to set the points of abeamcompass and the like.

One of the essential objects of this invention is to providea graduated device wherewith the points of such an instrument as va beam-compass; a dividers, a trammel, and the like, can beset to 'a minute degree of accuracy.

Another object o1' this invention `is ltorprovide a graduated device wherewith it is possible to set the points of a beam-compass and the like conveniently and to a more minute yextent than is possible with the use of the current graduated scales that are now generally, utilized for that purpose. y

Another object of this invention is to provide such a devic-e whereby the compass points can be set to a'high degree of accuracy, and which device can be produced economically,.as by producing a special member which is minutely and specially graduated and which is arrangedk to be used in conjunction with a known graduated scale that is .inexpensive and can be obtained-in the open market, such as a mechanics scaleof known construction.

position, Without any `clamping frame, `lont the scale being set against an abutment.

Fig.6 is an enlargedffragmentaryplan View of Vthis form of the invention.

Fig. -7 is a fragmentaryplan view'showingthe `v invention in a slightly. modified gform, wherein one end of the scale is notched, Ito engage the side of said member vand compensate fior :the offset 'or distance from said iside to the initial endfof thesetting line that isprovided 4on said member.

Fig. 8 is a vertical sectional view `of this form, takenon line 8-18 ofFig. 7.

Fig. 9 is a plan viewshowing` thisfnventicn in another modified form, wherein the special member is disk-shaped .and the' setting :line thereon is spiral-shaped'while the .clamping .frame supports said member Arotatably `.and `re- A further object of this invention is to provide such a device inseveral preferred forms, Ato suit the various desiresl of the different users and the various purposes for Whichrsuch .device may `be utilized. v v v These and various other'objects and advantages are attained with this invention, as will become apparent from .the following description,

ltaken in connection with the accompanying drawings wher-ein the invention is shown ina few of its preferred forms, it being evident that other arrangements and forms of construction may be' adopted for carrying out theobjects and purposes oi this invention. V

In the drawings:

Fig. 1 is a plan View illustrating an embodiment of this invention in one of its most desireable forms of construction, comprising the special member in conjunction with a, graduated scale of known construction and a clamping frame whereby they are secured together. 1 y

Fig. 2 is an end View thereof. f

Fig. 3 is van enlarged vertical sectional view, `taken on line 3--3 of Fig. 1. .Y

Fig. 4 is a vertical sectional view, .takenv online 4-4 of Fig. 2.

Fig. 5 is a plan view, at reduced size, showing the special member in conjunction-with a gradceives and holdsthe scale in position.. v .FigflO is la verticall sectional view thereof, taken ion line lil-L0 of Fig. 9. i

- fFig. .'11 is a fragmentary view showingthe esy sential parts of this form on an enlarged scale.

Fig. 12..illustrates a further modied form of vthe invention, wherein theyspecial ymember vis -in'the form of a drum and vthe setting line isy .engineers generally use, comprises among its y graduations vone set containing r10.0 graduation lines per inch, but is not graduatedner than y.such lines per inch. Thereby-it is difcultto set the compass points accurately to any greater degree of flneness than 1/100 of an inch. It is' also impractical to calibrate such usual `s cale. much finer than stated above, or as ne asseveral 100 lines to the inch, since then the graduation llines become too fine to construct and also become too .dcult to read readily on the ban-shaped scale -of vpractical size, usually 12-inches in length.

-I have thereiore'providedmy improved Vdevice whereby .the points of a beam-compass .andthe Ylike can be set to a -much liner-degree of accuracy than has been done so far with the cus? tomary means. With my invention, in either of its forms disclosed herein, I. providega :special and' finely graduated member and` arrange it so that-fit can ybe used in conjunction with a known scale l bearing standardgraduations, :including graduated scale and the ,two placedin an operative .55

ynations containing 16 lines to liooflinesperinch;

special member I 'arrange to use in conjunction with a graduated scale of known and substantially standard construction and bearing the known graduations ther-ecn, as is indicated by the scale 22 in Figs. 1 to 6, by the scale 22 in Figs. 7 and 8, by the scale 42 in Figs. 9, 10 and 11, and by the scale 62 in Figs. 12 and 13.

The scale 22 is of the customary and substantially standard bar-shaped or straight-edge construction which bears the usual graduations 23 thereon, which in this form illustrated in Figs. 1 to 6 comprises 100 lines to the inch; and said scale has one end 24 thereof set in selected position against the side of member 2| and perpendicular thereto, as indicated in the drawings; and as said graduations on the scale 22 are used for obtaining the full inches and main parts of an inch desired for setting the compass points, it is only necessary to graduate these lines so as to comprise 10 lines per inch, while the conjoined member 2| is graduated and arranged to provide the extremely minute part of the desired distance between the compass points.

It should be noted that altho these graduations are shown herein as being upon a mechanics scale and as comprising 100 lines per inch, as are also the graduation lines on member 2 l they may also be differently divided, as on an architects scale and the like; and such member and scale may likewise be graduated according to the metric system, including millimeters and the like.

In Figs. 1 to 6`of the drawings the special member 2| is showny in the form of a bar-shaped scale, quite similar in construction to the graduated scale 22, thereby tending to provide econonly in its manufacture. This member 2| bears on its upper face 25 graduation lines 2B; and

.in this` form these lines comprise 100 lines per inchover the length of said member, and are positioned adjacent one side 21 of the member which is a straight side and against which the end 24 of the scale 22 is abutted in its operative position. Said graduation lines 26 extend perpendicular to said side 21.

The member 2| is provided with a special setting line 28, which is a straight line in this form, and it extends substantially from one end of said member to the other, at least for a length of l inches thereon. This setting line 28 extends in a direction diagonal to said graduation lines 2B, and it slants from one of its ends 29 to the other end 30 at a uniform rate of increase away from the side 21. Said setting line 2B and also said graduation lines 2S are herein shown asbeing placed closely adjacent the side 21, with the setting line extending or cut across the graduation lines.

The setting line 28 is out or etched on the face 25 of the member 2| to provide a slight groove thereon, and it is shown in an exaggerated manner in Fig. 3. Said line is inclined or slanted at a uniform rate and at such a rate-that on inches lengthwise of said member its increment,

that is the distance this line advances away from side 21, will increase 1% of an inch; and thus in one inch lengthwise of said member 2| the distance or increment will be increased by 1,500 of an inch. Consequently, since one inch lengthwise of this member 2| bears 100 graduation lines, taken from the zero end toward the 10 inch part of said member, each one of these graduation lines increases, over its preceding line, in its distance from said side 21 to said setting line 28, vby i400 of 1/100 oi an inch, that is, by 1;!10000 of an inch. Then, by placing such a scale 22 with its end 24 abutting against the side 21 to extend perpendicular to said side, in the proper 1- position where the minute part of the desired A measurement can be obtained from this setting pass and a dividers and the like can be set readily and accurately to a iineness of $40000 part of an inch.

It should be noted, that since it is diicult to start this setting line 28 exactly at the corner at the zero end and the side 21 of member 2|, and to retain it clearly visible at such corner after extended use, it is preferable to start said line a slight distance away from said side 21, as illustrated herein. Such distance or offset 3|, bctween said side 21 and the initial end 29 of said line 28, is preferably equal to 1/10 of an inch, so that the point of the compass which is set on the graduation line on the scale 22 can be set conveniently on the line at V10 inch closer than the length desired to be used on the scale.

As an illustration, it is indicated in Fig. 1 how the points of a compass or dividers or the like can be placed for setting the points at 5.203 inches. One point is set at the 5.1 graduation line on the scale 22, while the other point is set on the setting line 28 on member 2|, at its thirtieth graduation line. This provides the setting of 5.203 inches, which includes the full 5.1 inches on the scale 22, and the 'es of an inch for the oiset at the initial end 29 of said line 28, and the additional distance or increment of 3%0000 or 0.003 of an Yinch provided by the slantr. ing of said line 23 at the .point of the thirtieth division along the length of said member 2|.

The form and parts of this invention as described above, and as it is substantially shown in Fig. 5 of the drawings, can be efficiently used and will serve the purpose of this invention; but it is preferable to set the outer end of the scale, that is away from member 2|, against an abutment 3|', to retain the scale joined with member 2|, as shown in Fig. 5. It is furthermore advantageous to provide retaining means for engaging and holding the scale iirmly in its operative position abutting with its end 24 against the side 21 of member 2|; and in Figs. 1 to 6 such retaining means is indicated as a frame 32 including a seat 33 and a seat 34 for receiving, respectively, the member 2| and the scale 22 placed perpendicular to member 2|, while elements 35 and 36 are associated with said seats 33 and 34 and have nuts 31 and 38 adjustable thereon, for clampingly securingfsaid member Y tion of. a knob 18 which protrudes from the drum opposite to said side B1.

This form of the device, like the several forms described above, is thus also arranged and constructed for use in setting the compass ypoints accurately to the 1/10000 part of an inch. I claim: Y

1. A device adapted to be used in conjunction with a graduated bar-shaped scale of substantially standard construction bearing standard graduations, wherewith to set the points of a beam-compass and the like to a minutely accurate degree, said device comprising a member containing a face and a side which provides a boundary for said face, adapted to have said scale placed with one end against said side, so as to extend the scale perpendicular to the side and be readily removable, said face bearing minutely divided graduation lines which extend each perpendicular to said side and also bearing a setting i line extending in a direction diagonal to said graduation lines and slanting at a uniform rate of increase away from said side, whereby, in setting the compass points, the scale is properly placed with its end abutting said side, and one point of the compass is set in proper position on said setting line while the other point is set in proper position on the graduation' on said scale` 2. The subject matter set forth in claim 1, and wherein a frame is provided for adjustably holding thescale end against the side of the member, and a setting nger is provided on the frame to facilitate setting the compass points readily and accurately.

l3. A device, wherewith to set the points of a beam-compass and the like, comprising a vgraduated bar-shaped scale of substantially standard construction bearing standard graduations thereon, also, a cooperating member which contains a face and a side against which side said scale is placca-ble freely and detachably with one end so that the scale and its graduations extend perpendicular to said side, said face bearing relatively finely divided graduation lines and also bearing a setting line which extends in a direction diagonal to said graduation lines and slants at a. uniform rate of increase'away from said side, adapted to have one point of the compass set in position on the setting line while the other point is set on the proper graduation on the abutting scale.

4. The subject matter set forth in claim 3, and

, construction and bearing a set of standard graduations thereon, also a cooperating member which contains a face and a side adjoining the face and which also includes frame means for securely supagainst which side the operative part end of the scale is detachably abutted in operation, said face bearing relatively many closely adjoining graduation lines thereon adjacent said side and also bearing a setting line adjacent the side and extending diagonally of the graduation lines and at a uniform rate of increase away from said side, means for supporting said member and retaining said operative part of the scale firmly in position abutting against said side but enabling ready withdrawal of said scale, and guide means to facilitate setting the compass points, whereby one of said points can be set on the setting line while bearing against said guide means and the other point set on the proper position on said vscale graduation, to serl the compass points to an extremely accurate degree.

6. A device, wherewith to set the points of a beam-compass and the like, comprising a barshaped mechanics scale of standard construction bearing standard graduations thereon, also a substantially bar-shaped scale member which contains a face and a side adjoining the face and against which side one end of said scale is abutted -in operation, said face bearing closely positioned graduation lines thereon and also a setting line adjacent said side and extending diagonally across the graduation lines and at a uniform rate of increase away from said side, frame means for adjustably holding the end of the scale iirmly abutting against said side, and a guide nger on the frame means to facilitate setting the compass points, whereby said points can be conveniently set to a high degree of accuracy.

7. A device, wherewith to set the points of a beam-compass and the like, comprising a barshaped mechanics scale bearing well known graduations thereon, also a cooperating member which contains a face and a side which bounds said face and against which side said scale is freely abutted with one end to extend said scale perpendicular to said side and to have their graduated top faces in the same plane, said face bearing minutely closely positioned graduation lines thereon and also a setting line adjacent said side and extending diagonally of the graduation lines and at a uniform rate of increase away from said side, from one end of the setting line to the other, and frame means for adjustably holding the end of the scale rmlyin position against said side.

8. The subject matter set forth in claim '7, wherein said member is substantially in the form of a bar-shaped mechanics scale of substantially standard construction and the setting line thereon is in the form of a straight line, whereby the compass points can be set accurately and precisely by setting one of the points in the intersection of the setting line with a graduation line, and setting the other point in position on the proper graduation line on said abutting scale.

- ALOYSIUS S. MCDONNELL. 

